i'd say you are probably taking too many supplements
at your age the liver should be able to heal itself , taking too much could just be overburdening it
possible cause for your liver problem is stress , since you are doing your exams at this time.try stress relieving techniques and learn to breathe properly if you are not already - that is breathe through the stomach area and not the upper chest.i am sure there are many articles on this on the web.